Process of forming leather substitutes.



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EMIL WEINHEIM, OF NEW YORK, N. Y.

PROCESS OF FORMING LEATHER svnsrr'ru'rns No Drawing.

To all whom it may concern:

Be it known that I EMIL WEINHEIM, a citizen of the United tates, and aresident of the city, county,

provements in Processes of Forming Leather Substitutes, set forth in thefollowing specification. 1

This invention relates of a textile fabric into substitute leather, andmore particularly to the method of preparing the leatherfying dope to beemployed, and has particular reference to the condition of thisleatherfying dope at the time of its application to the textile fabric.

Leatherfying dope, as employed in this art, varies somewhat in itsingredients, but usually has consisted of a solution of certainsubstances such as cellulose, nitro-cellulose, and their derivatives,and partially oxidized oils in volatile solvents such as alcohol, andderivatives of wood oil and coal, into which solution has beenmixedsuitable pulverulent coloring matter and fillers, so

that the resultant dope is partially a solution, partially an emulsionand partially a mixture, but which has always acquired a large amount ofits. fluidity through .the means of its incorporated volatile solvent.It has been the practice to apply this dope tov a moving strip oftextile fabric through the medium of suitable machinery, as for examplesuch as that set forth in my copending application, Serial No. 130,930,filed Nov. 11, 1916, for a method of completely lmpregnating' textilefabric with filling materlal. After certain manipulation to work thedope into the fabric, the fabric has been run through heated curing ordrylng rooms for the purpose ofdriving out the volatile solvent andmoisture, if the lat-' ter be present. As heretofore practised, it hasbeen customary to make a number, even as 1n"any as ten, applications ofthe leatherfymg dope to the fabric with an intermedlate passage throughthe curing room prior to each successive application. Notwithstandingthe relatively thin layer of applied dope by this repeated applicationprocess,

it has been difiicult toprevent pin-holes in the coating due to theescape of the volatile solvent in thecuring room. Pin-holes greatlyinjure the value of the finished prod not. This old process has alsobeen costly, due to the loss of the volatile'solvent in the curing room,so thatatt'empts have heretoand State of New York, have invented certainnew and useful 1m-' to the converting advantage has of course been 'Forexample, it is -lin, tri-acetyl Specification of Letters Patent.Patented Apr. 16, 1918. Application filed November 14, 1917. Serial No.201,989.

fore been made to reclaim the volatile'solvent from the heated curingair, but the expense of the reclaiming has about approximated the valueof the product reclaimed. Furthermore there has been great danger due toexplosions when the volatile solvent has been, of necessity, mixed inlarge quantities with the heated curing air. This disindependent of theexpense attendant upon the loss of the volatile solvent.

More specifically "t is an object of my invention to overcome all of thedisadvantages and defects in the processes outlined above.

an object of my invention to reclaim all the volatile solvent employedin making the dope in a cheap, safe and convenient manner. It is afurther object of the invention to reduce the number of necessarycoating applied to a textile fabric in changing ,it into substituteleather. I contemplate the production of a high-grade substitute leatherby means of a'single application of leatherfying dope and also the totalelimination of pin-holes. It is a further object of my invention tocheapen and make more safe the curing of substitute leather and moreparticularly to ,make possible the employment in the curing or dryingroom of unheated, clear, conditioned air to effect the complete curingof. the finished product.

By conditioned air I mean air which has been freed from moisture.

The above and further objects,.features and details of my invention willbetter be understood by reference to the following de-' claim to thediscovery of any new materials to produce a suitable to be employedbutcontemplate the emleatherfying dope,

ployment of any and all materlals as heretofore employed in the art, andas, for example, tion referred to above and as set forth in the PatentsNos. 601,325, 719,787, 885,219,

1,020,499, 1,048,912. In employing cellulose derivatives such asgun-cotton pyroxycellulose, and so fort in this lose derivative inquestion is art, the cell procured and is initially employed in makingthe dope in a water-moist state, the

water reducing its explosive quality. 1 1.c-

cording to my invention, 1 make up ina set forth in my copending applicamaining ingredients to form a satisfactory dope. When this stage in myprocess has been reached, which is the same as the process hereto-forepractised, l depart radically from the old methods. While slowly mixinga dope containing a volatile solvent in a mixing vat, ll inclose the vatin steam coils, maintaining the motion of the paddles or-othermixingmechanism and cause the dope to be heated to a temperature ofabout 120" Fahrenheit. heating lf inclose the vat with a hood connectedby a suitable duct with exhaust mechanism, drawing the volatile matterfrom the vat together with all water moisture to suitable condensingapparatus, where it is immediately reclaimed. ll prefer to practise thispart of the processin an isolated plant of the type characteristicallyemployed in connection with manufactures subject to explosion danger. Inthis way the entire remainder of the plant for making my substituteleather may be rendered as safe as a textile mill. Care should be taken,as recited above, that the steam coils should not be caused to heat thedope until all of the elements have-been mixed cold and a completemixture or emulsion has been produced. ll have then found it safe,contrary to the belief heretofore prevalent in the industry, to raisethe temperature suficientlyto drive out all the moisture and the avolatile solvent.

After all the volatile solvent and mois-w ture has been driven from thedope, ll remove the resultant dope into a heatable resting tank providedwith slow moving mixing addles and keep it therein under a heat ofbetween120 and 140 Fahrenheit under the action of the slow moving paddies for approximately twenty-four hours.

After this twenty-four hour treatment, the resultant dope,

exactly as has heretofore been done During this mixing and although ithas lost its volatile solvent, is extremely homogeneous I and issufficiently fluid for application to a moving textile fabric on accountof the temperature at which it is maintained. lit may then be applieddirectly to a moving textile fabric by apparatus such as that describedin my aforementioned co-pending application. However, I regulate thequantity applied to the textile fabric and the doctor blades so that asuiiicient amount is applied to complete the desired impregnation andcoating with one application. This is pos sible because there is nomoisture and no volatile solvent which must be expelled, and theexpulsion of which will cause pin-holes. After manipulation in suitableapparatus, as for example that described in my copending applicationaforementioned, T accomplish the final curing of the substitute leatherby passing through a curing room, preferably supplied with jets directedagainst the fabric of cleaned, dried air at atmospheric temperature.There is no neces sity of inclosing the fabric in an inclosure, as isnecessary in heated curing rooms. Furthermore, there is no necessity toprotect against explosions because there is no volatile solvent to causean explosion.

What is claimed and desired to be secured in a volatile solvent;admixing an oil; subjecting the mixture to heat in an inclosure;conveying away from said mixture the volatilized solvent; maintainingthe the resultant dope by the continued application of heat; andapplying said fluid dope free from volatile solvent directly to a bodyfabric.

2. The process of forming substitute leather comprising, dissolving afiller-base in a volatile solvent; mixing other dope in-.

.gredients in the resultant solution; driving out substantially all the,said volatile solvent; maintaining fluidity by heating; and

applying the resultant dope free from volatile solvent directly to abody fabric.

In testimony whereof T have signed my name to this specification,November, 1917.

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this 12th day of

